This invention relates to a method and an apparatus for operating a feeding device for fiber material, such as a boxed feeder assembly in which the fiber material is deposited on the upper side of an endless supply belt which is supported by two rotary end rollers and which is driven at low speed. As the upper (conveying) flight of the supply belt is moved in a forward direction, the fiber material thereon is advanced to a steeply upwardly inclined spiked lattice which carries the fiber material upwardly.
It has been found that as the spiked lattice carries away material from the fiber pile, in the upper zone of the fiber pile the material is not removed as satisfactorily by the spiked lattice as in the lower zone where the empty spikes may penetrate into the fiber pile from below and where a relatively large pressing force prevails. This leads to a rolling in the upper zone and to an undesired increase of the pile material immediately adjacent the spiked lattice. This leads to disadvantages in the blending of the fibers and to operational difficulties in the machine, particularly at high outputs.
In a known method the fiber supply belt is driven at constant speed which affects in a large measure the output of the machine. The speed of the spiked lattice, the fill height as well as the pressure of the piled-up fiber material also have an effect on the output. The above-noted rolling causes nonuniform pressing forces and continuously fluctuating fill heights. It is particularly of disadvantage that the upper, lighter layers of the fiber pile have significantly reduced chances to be entrained by the spikes since the latter have already been filled in the lower zones, particularly because of their favorable arrangement and the high pressing forces there. Such high pressing forces are present in the lower zone because of the greater, weight-caused compression and the closer proximity of the material to the supply belt where the feeding forces are still highly effective.